Mobile devices that can communicate over more than one type of telecommunication network have become increasingly prevalent. For example, dual-mode mobile phones may allow a consumer to connect to wireless wide area networks (WANs) as well as wireless local area networks (LANs). When accessing a cellular WAN (including, but not limited to, networks based on the Global System for Mobile Communications (GSM), IS-95, Universal Mobile Telecommunications System (UMTS), and CDMA-2000 standards), the mobile device may be connected to other mobile or fixed devices or services via a circuit-switched network architecture. When accessing wireless LAN connections (including, but not limited to, networks based on the IEEE 802.11 wireless fidelity (Wi-Fi) standards), the mobile device may be connected to other mobile devices or services via a packet-based network architecture, such as an Internet Protocol based (IP-based) network architecture. Networks that allow mobile devices to access a service provider's core network via wireless LANs are often referred to as Unlicensed Mobile Access (UMA) or Generic Access Networks, since they allow wireless service providers to merge their cellular networks with IP-based wireless networks and provide seamless network service for mobile devices of subscribers.
As used herein, the phrase “mobile device” is broadly intended to refer to portable devices which are capable of accessing wireless networks for voice and/or data communications. Mobile devices may therefore include, but are not limited to, phones, smartphones, tablet computers, notebook computers, laptop computers, personal digital assistants (PDAs), multimedia devices, gaming devices, or other similar mobile devices. As such, mobile devices range widely in terms of capabilities and features.
One challenge of multi-mode mobile devices is connecting a mobile device to emergency services based on the current location of the device. For example, telecommunications service providers may need to route certain calls, such as “911” or other emergency calls, to a public safety access point (PSAP) that is associated with the geographic location of the mobile device. Service providers who operate cellular networks with fixed network infrastructure have a variety of techniques that are available to determine the location of the mobile device within the fixed network infrastructure. Service providers who also allow access through LAN access points have a variety of other techniques that are available to determine the geographic location of the mobile device. The methods used to determine location of mobile device in a cellular network, however, are typically different than the methods used to determination location in a LAN. Such differences may result in a greater or lesser degree of accuracy, reliability, and desirability depending on the circumstances and the type of location determination techniques that are used. In circumstances in which a dual-mode mobile telecommunication device is able to communicate with either a WAN or a LAN, determining which network to access can therefore be a complicated problem.